Automatic filtermass press

ABSTRACT

An automatic filtermass press having a table mounted for rotation on a vertical shaft, with a plurality of screens on the table, a vertically movable forming cylinder above the table, and a movable ram within the cylinder; is provided with improved means for sequentially positioning the screens beneath the forming cylinder and improved means for moving the ram up and down. A circular indexing plate is mounted on the vertical shaft. The plate is displaced from the rotary table and shielded from the filtermass. The plate has notches around its periphery corresponding to the screens on the rotary table. The indexing plate is locked in place by a reciprocating locking member which moves into and out of the notches. A hydraulic rotary actuator is connected to the indexing plate and the rotary table by a one-way clutch. The ram is moved up and down by a double acting hydraulic cylinder supplied with water by a recirculating system which is adapted to exert the maximum pressure on the ram when the ram reaches the end of its pressing stroke. The system includes a reservoir with an overflow that maintains a substantially constant volume in the reservoir. The inlet of a centrifugal pump is connected to the reservoir, and the discharge of the pump is connected to a four-way valve which is adapted to connect either end of the hydraulic cylinder to the discharge of the pump while connecting the other end of the cylinder to the reservoir. A bleed line, which contains flow restricting means such as a needle valve or back-pressure valve, connects the pump discharge directly to the reservoir.

United States Patent [191 Nunlist et al.

AUTOMATIC FILTERMASS PRESS [73] Assignee: Sybron Corporation, Rochester,

[22] Filed: Apr. 26, 1972 [21] Appl. No.: 247,755

[52] US. Cl 100/269, 60/329, 100/110, 100/223 [51] Int. Cl B30b 1/32, B30b 9/06 [58] Field of Search 100/269 R, 110, 223; 60/477, 478, 488, 329

[56] References Cited UNITED STATES PATENTS 1,982,711 12/1934 Vickers 100/269 R 2,092,092 /1937 Sinclair et al. 100/269 R X 2,220,798 11/1940 Dinzl..... 100/269 R X 2,560,749 7/1951 Stacy 60/329 2,560,906 7/1951 .Thyen 100/269 R X 2,646,745 7/1953 Seltzer 100/269 R X 2,714,349 8/1955 Johnston 100/73 2,752,847 7/1956 Vandenburgh... 100/269 R X 2,929,212 3/1960 Lewis et a1 60/488 X 3,498,061 3/1970 Prucha et a1 60/329 3,643,824 2/1 972 Patridge 100/269 R FOREIGN PATENTS OR APPLICATIONS 212,712 1/1961 Austria 415/53 438,615 1 H1935 Great Britain 60/329 Primary ExaminerPeter Feldman Attorney, Agent, or Firm-Theodore B. Roessel; James A. Rich Dec. 31, 1974 [57] ABSTRACT An automatic filtermass press having a table mounted for rotation on a vertical shaft, with a plurality of screens on the table, a vertically movable forming cylinder above the table, and a movable ram within the cylinder; is provided with improved means for sequentially positioning the screens beneath the forming cylinder and improved means for moving the ram up and down. A circular indexing plate is mounted on the ver tical shaft. The plate is displaced from the rotary table and shielded from the filtermass. The plate has notches around its periphery corresponding to the screens on the rotary table. The indexing plate is locked in place by a reciprocating locking member which moves into and out of the notches. A hydraulic rotary actuator is connected to the indexing plate and the rotary table by a one-way clutch. The ram is moved up and down by a double acting hydraulic cylinder supplied with water by a recirculating system which is adapted to exert the maximum pressure on the ram when the ram reaches the end of its pressing stroke. The system includes a reservoir with an overflow that maintains a substantially constant volume in the reservoir. The inlet of a centrifugal pump is connected to the reservoir, and the discharge of the pump is connected to a four-way valve which is adapted to connect either end of the hydraulic cylinder to the discharge of the pump while connecting the other end of the cylinder to the reservoir. A bleed line, which contains flow restricting means such as a needle valve or back-pressure valve, connects the pump discharge directly to the reservoir.

1 Claim, 7 Drawing Figures s: .1 231$ I OVER 3 70 L FLOW I 71 72 l 69 a 687 2 l 67 f l 73 MAKE UP 75 WATER l PATENTED [1583 1 I974 sum 1 nr 4 all,"

FIG. I

PATENTED [H3 1 I974 SHEET 2 [IF 4 VIII/fill FIG. 4

BACKGROUND OF THE INVENTION This invention relates to an automatic press for producing filtermass cakes, which are generally produced by building up a cake of fibers, such as cotton or the like, from a dilute slurry. One process and apparatus for producing these cakes are disclosed in US. Pat. No. 2,714,349 to H. S. Johnston. An automated version is illustrated in the September 1953 issue of American Brewer at pages 43-44. This press has a table mounted for rotation on a vertical shaft. A plurality of screens are spaced about the table, a vertically movable forming cylinder is positioned above the table, and there is a movable ram within the cylinder.

SUMMARY OF THE INVENTION It is an object of this invention to provide improved means for sequentially positioning the screens on a rotary table such as the one illustrated in American Brewer beneath the forming cylinder. The invention provides a circular indexing plate mounted on the same shaft as the rotary table but displaced from the table. The indexing plate is isolated from the filtermass, which helps prevent jamming of the controls associated with the indexing plate. Notches are spaced about the periphery of the indexing plate. These notches correspond to the screens on the rotary table. A locking member, and means for reciprocating the locking member into and out of the notches, lock the indexing plate and the rotary table in position while a filtermass cake is being produced and then permit rotation of the plate and table so that the next screen can be positioned beneath the forming cylinder. The plate and table are rotated by a rotary actuator connected to the plate and table by a one-way clutch.

Another object of this invention is to provide a system for moving a ram such as the one illustrated in American Brewer up and down which reduces the water requirements of the system.

A further object of this invention is to provide means for moving the ram up and down that exerts the maxi mum pressure on the ram when the ram is at the end of its pressing stroke.

According to this invention, the ram is powered by a double acting hydraulic cylinder supplied with water from a recirculating system including areservoir with an overflow that maintains a substantially constant volume of water in the reservoir. The inlet of a centrifugal pump is connected to the reservoir, and the discharge of the pump is connected to a four-way valve which is adapted to connect either end of the hydraulic cylinder to the discharge of the pump, while connecting the other end of the cylinder to the reservoir. Thus, water is continually reused in this system. A bleed line connects the pump discharge directly to the reservoir. This bleed line contains flow restricting means such as a needle valve or back pressure valve. As a result, when the ram reaches the end of its pressing stroke, the pump operates at a lower flow rate and produces a higher discharge pressure. Thus, the maximum pressure is exerted on the ram when it is at the end of its pressing stroke; and the ram exerts the greatest pressure of the filtermass cake at the end of the pressing cycle, when more pressure is needed to squeeze the last increment of water from the cake.

Other objects and advantages of this invention will be apparent from the following description.

DRAWINGS used to insure precise alignment of the rotary table on the press shown in FIGS. 1 and 2..

- FIG. 4 is an enlarged cross-sectional view taken along lines 4-4 of FIG. 2, showing the means for rotating the table and locking it in position.

FIG. 5 is a cross-sectional plan view, taken along lines 55 of FIG. 4.

FIG. 6 is a schematic of the hydraulic-pneumatic system which rotates the table.

FIG. 7 is a schematic of the hydraulic system which moves the ram up and down.

DETAILED DESCRIPTION Referring to FIGS. 1 and 2, the press has a table 10 mounted for rotation on a vertically extending shaft 11. The table has three screens 12 mounted in circular frames 13 which in turn are supported by the spokes 14 and the rim 15 of the rotary table 10. By rotating table 10 on shaft 11, the screens 12 can be sequentially posi tioned beneath a forming cylinder 20. The cylinder 20 is supported by two rods 21 connected through a rack and pinion drive (not shown) to a hydraulic cylinder (not shown) that moves the forming cylinder 20 up and down. The screen positioned beneath the forming cylinder is supported by a plate 17 attached 'to the frame 18 of the press. The frame 18 also defines a catch basin 19 for the water pressed from the filtermass.

As is best seen in FIG. 4, when one of the screens has been rotated into position, the forming cylinder 20 is lowered into the circular frame 13 in which that screen is mounted. Vertically tapered'wedges 16, which may be seen in FIGS. 1-3, are mounted on' the spokes 14 of the table 10. These wedges are positioned so that if the table is slightly out of position as the forming cylinder descends, the forming cylinder will contact one of the wedges and move the table into the precise operating position.

A perforated ram 22 is mounted for reciprocation within forming cylinder 20 by a double-acting hydraulic cylinder 23. When the forming cylinder has been lowered into position, and the ram has been raised to the top of the cylinder as shown in FIG. 1, a measured amount of a slurry containing the filtermass is admitted to the forming cylinder 20 from a measuring hopper (not shown) through line 24. The ram then moves down to the position shown in FIG. 4, whereby the water is pressed from the filtermass 25. The water escapes through screen 12 and through the perforated ram 22. When the ram has reached the bottom of its stroke, the forming cylinder is moved vertically to let any water that has accumulated on top of the ram drain off. The ram is then raised again and the table 10 is rotated to bring another screen 12 into position beneath the forming cylinder 20.

The means for rotating the table 10 and locking it in position may be seen in FIGS. 4 and 5. A circular indexing plate 30 is mounted on the shaft 11 which also supports the rotary table 10. As is best seen in FIG. 4, the indexing plate 30 is isolated'from the catch basin 19 by the frame 18 of the press. This helps keep the indexing plate and the controls associated with it clean, which reduces maintenance problems.

The indexing plate 30 has a plurality of notches 31 spaced about its periphery. Each notch 31 corresponds to one of the screens 12 on the rotary table 10. A locking member, consisting of a cam roller 32 mounted on the piston rod of a spring loaded pneumatic cylinder 33, is mounted adjacent to the plate. The pneumatic cylinder moves the cam roller 32 into and out of the notches 31 in the indexing plate, thereby alternately locking the indexing plate and the rotary table in place and freezing them so that the next screen can be rotated into position.

The motive .power for rotating the indexing plate and table is supplied by a hydraulic rotary actuator 40. The output shaft 41 of the actuator is connected by a coupling 42 to a one-way clutch 43 mounted on the shaft 11 which also supports the indexing plate 30 and the rotary table 10.

As may be seen in FIG. 6, the rotary actuator 40 consists of two double-acting cylinders in parallel, a primary cylinder 46 which is the power cylinder and a secondary cylinder 47 which is the chain return or seal cylinder. Primary and secondary pistons 48, 49 are suspended in series on an endless chain 50 which passes over a sprocket 51 on the output shaft 41, and also over -an automatically tensioned idler 52. Hydraulic fluid is supplied to either the drive head 53 or the idler head 54 from one of two hydraulic-pneumatic accumulators S5, 56. In FIG. 6, air is being supplied under pressure through a four-way valve 57 to the right hand accumulator 55, thereby forcing hydraulic fluid from that accumulator into the drive ,head 53. The left hand accumulator 56 is vented to atmosphere through the four-way valve 57, which allows fluid from the idler head 54 to be forced into the left hand accumulator 56. As a resuit, the larger primary piston 48 is moved to the left due to the differential pressure on the two pistons. This rotates the output shaft 41 clockwise. The one-way clutch 43 shown in FIG. 4 is arranged so that when the output shaft 41 of the rotary actuator 40 is driven clockwisethe circular indexing plate 30 and the rotary table are also rotated.

Preferably the rotary actuator 40 is connected to the accumulators 55 and 56 by relatively small lines58 and 59 in order to provide smooth rotation of the table. The flow restriction provided by these small lines helps to absorb any pressure fluctuations which occur if the table 10, shaft 11 or the like bind during any portion of their rotation, and keep them rotating smoothly.

Rotation of the table is triggered by the vertical movement of the perforated ram 22 which press the water from the filtermass. As the ram moves upward at the end of each pressing cycle, a rod (not shown) extending from the ram actuates a limit switch (not shown) and air is supplied to the inboard end of the locking assembly pneumatic cylinder 33, thereby moving cam roller 32 out of the notch 31 on the indexing plate 30 and freeing the plate and table 10 for rotation. At the same time the limit switch actuates controls which move the four-way table drive valve 57 to the position shown in FIG. 6, thereby forcing hydraulic fluid into the drive head 53 of the rotary actuator 40 and rotating the table 10 and indexing plate 30 clockwise. Referring to FIG. 5, after the indexing plate has rotated through a portion of its arc, a pin 34 contacts the actuathe cam roller 32 drops into the new notch, another pin 37 contacts the actuator 38 of another microswitch 39. This switch reverses the four-way table drive valve 57 and supplies air to the left hand accumulator in FIG. 6, thereby forcing hydraulic fluid into the idler head 54 of the rotary actuator and reversing the rotation of the rotary actuator output shaft 41. The rotary table 10 is now in position to produce a filter pad on the next screen 12.

FIG. 7 illustrates the preferred means for moving the perforated ram 22 up and down. Referring to that figure, the ram is connected to the piston 74 of a doubleacting hydraulic cylinder 23. The hydraulic cylinder is powered by water from a reservoir 65 having an overflow 66 which maintains a substantially constant amount of water in the reservoir. Any water expelled from the hydraulic cylinder 23 is recirculated to the reservoir 65, thereby conserving water. From the reservoir 65, water is supplied to the hydraulic cylinder by a turbine or other form of centrifugal pump 67 having an inlet line 68 connected to the bottom of the reservoir 65 and a discharge. line 69 connected to a four-way valve 70 which is adapted to connect either end of the hydraulic cylinder 23 to the discharge of the pump while connecting the other end of the'cylinder to the reservoir 65. The pump discharge'is also connected directly to the reservoir by a bleed line 71, which contains a valve 72 which restricts the flow through the bleed line. This valve is adjusted so that when the ram 22 reaches the end of its pressing stroke, the centrifugal pump 67 operates at a lower flow rate and a higher discharge pressure. As a result, the pressure'exerted on the ram at this point in the cycle is increased and the ram exerts the maximum pressure on the filtermass at the end of the pressing cycle.

In the simplest form, valve 72 may be simply a needle valve opened just enough to let enough water pass through the pump to cool the pump when it is running in this semi-stalled condition. With this type of valve, it is generally preferable to supply astream of make-up water through a line 73 connected to the pump inlet line 68 just upstream from the pump in order to provide the maximum cooling for the pump. This make-up water also helps prevent stagnation of the water in the system. If desired, a check. valve can be installed in line 68 between the reservoir and the junction with line 73 in order to keep the make-up water from flowing back into the reservoir.

In some cases, as for example, where the stalled part of the cycle is only a minor portion of the total cycle, the water may not need to be cooled. Thus, it may be desireable to add make-up water only when cooling is required. In the illustrated system, this is accomplished by installing an automatic valve 75, preferably a needle valve or some other form of throttling valve, in the make-up line 73; installing a temperature sensor 76 in the reservoir; and opening and closing valve 75 with signals from the temperature sensor 76.

In some cases, it may be desirable to use a back pressure valve in the bleed line 71 instead of a needle valve. With a back pressure valve, the system can be adjusted to provide slightly greater flow through the pump when the ram has reached the end of its pressing stroke,,and supply all of the pump discharge to the hydraulic cylinder while the ram is moving. The increased flow through the pump during the stalled part of the cycle reduces wear on thepump; and since there is substantially no flow through the bleed line while the ram is moving, the higher flow rates through the bleed line during the stalled part of the cycle do not affect the cycle time.

It should be understood that the embodiments of this invention described above are merely illustrative and that those skilled in the art may make modifications within the scope of this invention, which is defined by the appended claims.

We claim:

1. In a filtermass press having a vertically movable ram powered by a double-acting hydraulic cylinder, the improvement comprising a recirculating system for supplying water to said hydraulic cylinder comprising:

a. a reservoir with an overflow that maintains a substantially constant volume of water in the reservoir;

b. a centrifugal pump having its inlet connected to said reservoir;

0. a four-way valve adapted to connect either end of said cylinder to the discharge of said pump, while connecting the other end of said cylinder to said reservoir;

d. a bleed line connecting the pump discharge directly to the reservoir, said bleed-line containing voir exceeds a certain level. 

1. In a filtermass press having a vertically movable ram powered by a double-acting hydraulic cylinder, the improvement comprising a recirculating system for supplying water to said hydraulic cylinder comprising: a. a reservoir with an overflow that maintains a substantially constant volume of water in the reservoir; b. a centrifugal pump having its inlet connected to said reservoir; c. a four-way valve adapted to connect either end of said cylinder to the discharge of said pump, while connecting the other end of said cylinder to said reservoir; d. a bleed line connecting the pump discharge directly to the reservoir, said bleed line containing flow restricting means, whereby when the ram reaches the end of its stroke, the pump operates a a lower flow rate and produces a higher discharge pressure; and e. a make-up water supply line for supplying water to said system between said reservoir and said pump inlet, an automatic valve in said supply line, and a temperature sensor mounted on said reservoir, said temperature sensor being adapted to open said automatic valve when the temperature in the reservoir exceeds a certain level. 